Power mechanism



March 6, 1928. 1,661,710

- R. 5. THOMPSON POWER MECHANISM Filed Jan. 5. 1925 Patented Mar. 6, 1928. r I 's UNITED STATES RUSSELL G. THOMPSON, OF ROCHESTER, NEVI YORK, ASSIGNOR, BYMESNE ASSIGN- MENTS, TO NORTH EAST APPLIANCES INC., A CGBPORATION OF NEW YORK.

EOWER MECHANISM.

Application filed January 5, 192.5. Serial 1W0. 127.

This invention relates to power mechanism lei, which cooperate with an arm 15. This suitable for actuating the type-bars or other arm turns upon a pivot 16, between the sideparts of a typewriter or similar machine. members of the poiver-levcr, and it is con- The object of the invention is to produce trolled by a spring 17, coiled about the pivot a a simple, etlective and compact mechanism and engaging a lug 18 near the upper end for the purpose in question, which shall be oi the spring-arm 15. In the normal 1n capable of long use without undue wear. operative position of the cam, in which it To this end, the invention consists in the 1s slightly out of engagement with the roller, mechanism hereinafter described, as it is the spring-arm-presses against which ever one ie defined in the annexed claims. of the pins leimay be in the lower position,

in the accompanying drawings, F 1g; 1 15 as shown in Fig. 1, so that it the cam be rea side-elevation, partly in section, of power leased the arm causes it to turn sufliciently to mechanism embodying the resent invention, bring upper lobe into operative engageand Fig. 2 is a partial end-elevation, showing ment with the grooved surface of the powerparticularly the cam and its controlling roller.

d i The cam is normally restrained from rota- The invention is illustrated as embodied in tion by means of stopanechanism controlled power mechanism for actuating the typeby a key 7. This mechanism comprises a bars of a typewriter. Fig. 1 indicates the stop-lever 19, which swings about the pivot to platen 5 of such machine, and shows one of 16 and is provided, at its lower end, with 2'5 the type-bars 6 of ordinary form. This two stop-logs 20 and .21. The cam is protype-bar is thrown into operation under the videdwith two detents'iail which cooperate control of a key 7. It will be understood with the stop-lugs. Normally, one of the that the type-bar is one of the usual set or detents engiw s the lug 520, as shown in Fig.

5 series, and the key 7 is one of the usual set 1. The upper end 23 of the stop-ie er is constituting the complete keyboard ot the connected, by a rod 2a, with a bell-crank machine. lever :25 upon which the key 7 is mounted. The power for actuating the type-bar is This lever turns on a stationary pivot 26, derived from a roller 8, which is rotated and it is held in the normal position, shown 30 constantly by any suitable source of power, in Fig. l, by a spring 27. At this time a such, for example, as an electric motor. laterally bent lug at the upper extremity of This roller cooperates with a cam 9, con the stop-leverengages the edge of an opening sisting of sheet-metal and provided with a in one of the side men'ibers of the powerbeveled periphery 10. The roller is pro lever, as shown in Fig. 1. lVhen the key is vided with a series of annular beveled depressed the-stop-levcr is swung in a direce0 grooves, each groove being in line with the tion to move the log 20 out ot the path of edge of one of the cams. The cam, as shown, movement of the detent Q2, whereupon the has two similar lobes, and performs a haltspring-arm turns the cam as above described, rotation at each cycle of operatioii. It turns and the cam performs a half-rotation and to on a pivot 11 at the lower end of it powcrswings the power-lever. At the end of this lever 12. This lever comprises two sheethalf-rotation the cam is arrested by the enmetal side members, which are spaced apart gagcment of the second detent 22 with the attheir lower end to receive the cam, and stop-hr; 9.1,since the halt-rotation of the cam the sidemembers are connected by a pivot takes place before the operator can release the -15 13, about which the lever swin sQ It will be her. U )011 the subse uent release and rise 1'00 c: l. l

understood that when the cam is in rolling of the key, the lug 21 disengages the detent, engagement with the power-roller 8 it has but the detentis arrested, after a slight turnthe etl'ect of swinging the power-le=ver about ing moven'ientot the cam, by the lug 20, the. its pivot. parts being thus brought back to the normal 50 The movements of the card are controlled position. of Fig. l. by mechanism including a spring device for The pivot 13 turns in a bearing-member initiating the rotary movement by which the 28, which is supported by a crossbar 29 on cam is brought into engagement with the the frame of the machine. A. screw 30, 'roller. For this purpose, the cam is prothreaded into the bearing-member, secures .56 vided with two diametrically opposite pins the lattcrin place. In firstassembling the no machine, or in readjusting it, it is desirable that the normal clearance between the cam and the power-roller be exactly adjusted, and as a convenient means for performing this function, provision is made for adjusting the bearing-member horizontally upon the cross-bar 29. For this purpose an adjusting screw 31 is threaded into the bar, and is provided with a flange engaging a notch in the lower surface of the bearing-member. The opening in'the cross-bar, through which the screw 30 passes, is made large enough to permit the necessary lateral movement when the screw is loosened. The bearing-member is provided with a stop-lug 32 which is normally engaged by the ower-lever, and which determines the position of the lever relatively to the bearing-member. 'It will be evident, therefore, that by adjustment of the bearing-member the clearance between the cam and the roller may be exactly determined.

Where a type-bar or other part is actuated by a cam-operated lever of the type in question, it is desirable that pressure between the cam and the roller be maintained throughout the operative motion, so as to insure the continued rolling action of the cam and prevent it from slipping or from jumping out of engagement wlth the roller. This is particularl the case Where the engaging surfaces 0 the cam and roller are of metal or other material having a relatively low 00- eliicient of friction. Accordingly, a feature of the present invention resides in he use of a spring 33 which is attached, at one end, to the power-lever and at the other end to a lug on the bearing-member. This spring insures a steady frictional engagement between 'the cam and the roller throughout the cycle of operation of the cam.

A feature of the invention resides in a simple and direct mode of connection between the power-mechanism and the typebar. In previous power-mechanisms of the cam-and-roller type it has been the practice so far as the inventor is informed, to extend by means of a pull-rod 34. If these pull'- rods be made of sufficient length, such-direct connection is practical and permissible, regardless of the fact that the type-bars are pivoted on the usual segment and that this results in somewhat varying angles in the pull-rods.

In order that the spring 33 may have the intended result, it is necessary to prevent the type-bar, or other actuated member, from acting, during any part of its operative motion, to pull the cam away from the roller through the effect of the momentum gained during the early part of its motion. Accordingly some provision should be made for lost motion between the parts. In Fig. l accordingly, the rod 34 is shown engaged in an elongated opening 3:) in the upper end of the power lever. This permits the typebar to overrun slightly and to complete its operative stroke while the cam is still maintained in engagement with the roller by the spring 33, and without necessity of very exact adjustment of the mechanism.

It will be apparent that the effect of the beveled periphery of the cam, and the corresponding roove in the power-roller, is to create sufhcient frictional engagement between these parts to insure against slippage when they are rolling together, and that the use of metal such as hardened steel in these parts is thus made permissible, whereby a considerable degree of durability is secured, The cam mechanism, the owerdever, the bearing-member and the spring 33 constitute a convenient unitary assembly which may be readily mounted in the machine or removed therefrom for the purpose of repair or replacement. The direct connection between the power-lever and the type-bar greatly simplifies and lightens the operating mechanism, and pernnts rapid and positive action of the type-bars.

The invention is not limited to the embodiment thereof, hereinafter described and illustrated in the accompanying drawings, but it may be embodied in various forms within the scope of the following claims.

The invention claimed is:

1. Power mechanism, for a. typewriter or the like, comprising: a constantly rotary power roller; a power lever; a cam carried by the power lever and'coopcrablc with the power roller; a bearing-member, on which the power lever is pivoted, provided with a stop cooperating with the power lever to determine its normal inactive position, a spring, connecting the power lever and the bearing-member, tending to swing the power lever in the direction of said step; connections, between the power lever and the art of the machine which is to be actuated, taving provision for lost motion; and means for turning the cam into engagement with the power roller.

'2. Power mechanism, as in claim 1, in which means are provided for adjusting said bearing-member towards and from the power roller.

3. Power mechanism, for a typewriter or the like, comprising: a constantly rotary power roller, a power lever, a cam rotatably mounted on the power lever and cooperable with the power roller, the cam having an increasing radius so that when freely r0- teting in engegement with the roller 1t eeuses e swinging movement of the lever, a

\spring connected with the power lever and tending to swing it in the cilreetlon to move Bfihe cam bodily toward the roller, 8. stop for iimiting the mevement of the lever by the spring, means for turning the caminto initial engagement with the roller and for arresting its turning movement at each 0peretion, end connections; between the power lever and the part of the machine to be acmeted, havin prevision for 10st motion to permit sai part. to overrun the power mechanism without causing disengagement 0f the cam from the roller,

RUSSELL e. THOMPSON. 

